Discovery Magazine

Photo Credit: Mark Archambault

Regolith Dispersion from Rocket Plume Cratering During Lunar Landing

This project is devoted to developing a novel, integrated theoretical and numerical framework for characterizing the interaction between the rocket plume of a landing or launching vehicle and the lunar regolith, and the results of this interaction. It will bring together an understanding of physics, fluid dynamics, thermodynamics, computer science and applied mathematics. Describing this phenomenon in its entirety is very broad in scope, requiring extensive and detailed physical modeling of material properties, chemical reactions, particle dynamics, turbulent flow, and thermal and mechanical stresses to obtain an accurate prediction of how an engine plume will affect the lunar regolith and the surrounding environment. The present work focuses on developing and implementing models representing the behavior of the ejected material after it leaves the lunar regolith, its interaction with the surface and the engine plume, and where it comes to rest. In total, it is anticipated that an overall flow model will be developed to provide data towards investigating suitable landing site criteria, to assist in learning how planetary flight operations can impact nearby structures and activities, and to create a better understanding of the challenges of exploring our solar system.

This research is not only applicable to the lunar regolith, but also, with significant changes, to the Martian surface (Martian soil is made of particles eroded by wind, a gravitational field exists, and an atmosphere exists with wind conditions that must be accounted for); the same methodology could be used for asteroids. Outposts on the Moon could eventually be used as launching points for missions to Mars or other planetary bodies. Descent vehicles from previous unmanned missions to Mars have used aerothermal breaking to slow the descent followed by impact on the surface. Such landing systems are imprecise and ill-suited for continuous Martian operations, and ineffectual for asteroid-related operations. Controlled landings will require thrust engines in close proximity to the surface. Thus, early Martian missions will encounter challenges similar to those associated with the lunar regolith until permanent flight facilities can be established. By changing input conditions such as atmospheric density and pressure, soil composition and texture, and gravity, the proposed models and algorithms will be able to predict how the Martian surface will behave when a rocket plume impinges on its surface.